WO 2009/028369 discloses an electric machine formed as a linear motor including a stator and a mover capable of reciprocal linear motion with respect to the stator. The mover of the linear motor includes a permanent magnet array including a plurality of permanent magnets arranged such that magnetic poles having the same polarity face each other. The stator of the linear motor includes winding portions formed by winding a winding conductor in a coil and concentrically disposed with the permanent magnet array. For the electric machine formed as this type of linear motor, it is desired to enhance thrust of the mover per unit volume. Thus, it is conceived to increase the number of winding portions, and to increase the size of the winding portions.